Diazonamide A is a mitotic spindle-disrupting agent first isolated from the marine organism Diazona angulata, having the structure:

The preparation of diazonamide analogs via macrocyclic indoline intermediates bearing a carbobenzyloxy (Cbz) or o-nitrophenylsulfonyl protected amino group has been previously described. U.S. Pat. No. 7,022,720 correctly discloses the structure of diazonamide A and describes the synthesis of some of its analogs. U.S. application Ser. No. 11/264,502, a continuation-in-part of U.S. application Ser. No. 10/227,509 (now U.S. Pat. No. 7,022,720) was filed 31 Oct. 2005, and is published as US 2006/0089397. U.S. Ser. No. 11/591,016, a continuation-in-part of U.S. application Ser. No. 11/264,502, was filed 31 Oct. 2006, and is published as US 2007/0149583. U.S. application Ser. No. 12/134,984, filed 6 Jun. 2008, and published as US 2009/0005572, describes synthetic methods for the preparation of diazonamide analogs via indoline intermediates.